Piston mechanism for internal-combustion engines



July l, 1930. ,Jj c'. LEARY: 1,769,376

PISTN MECHASM FOR INTERNAL COMBUSTION ENGINES Filed July 24, 1924 F1a1-y Flag I NVEN TOR.

Patented 'July l., 1930 JOHN c. LEAnY, Orsini rzaanorsoo, onLIFonnI-n lApplication filedy July a4,

v invention'relatesto, means for lquickly and easily removingthefpiston-head from an internal combustion engine andor varying thecompression space in saidv vinternal combustion engine. n u' An objectof the invention'is to provide a piston-head that Can be readilydetached from the wristpin, and withdrawn through what is generallycalled the head end of an .internal combustion engine, withoutdisturbing the crank-ease or crank-pin bearings. Another object. is toyprovide a meansvby which the compression space vcan be readily varied.VVY; y Y

The invention possesses other objects` `and featnres ofadvantage, someof which'with` the foregoing will be setfortli in the followingdescription of the preferred form of my invention, which is illustratedinthe drawings accompanying and forming part of the specification. lt isto be understood that'l do not limit `myseliifto the showing made byVthe said drawings and description, as I may in the Claim.

lReferring to the drawings.

Fig. 1 is a front elevation of an ordinary internal combustion enginewith shell broken with my preferred device.

, Fig. 2 is a sectional view of what will hereafter'be referred to asthe outer shell.

Fig. 3 is a plan view of the Vhead of this shell. Y

`F ig. 4 is a sectional side view of what is called the inner shell (orspider) showing Wrist pin bearings, bosses for bolts, andfconnecting rodsuspended.

Fig. 5 is a. plan view oiithis inner shell. Fig. 6 is the outer'shell ofa piston with a straight bore referred to in specifications.

Fig. 7 is a sectional view of inner shell or spider for Fig. 6.

ing` when once screwed'up.

Fig. 9 is an alternative device for keeping bolts romturning.

" k Figure 10 is a perspective View of a distance adopt variations fromthe preiierredl forni n Within the scope of my invention, as set forthto show a sectional view of a piston equipped'- Jofrnixtnre can beobtained.

1.99.4.' .serial"Nof'zzzes f piece for use in the embodiment oli'Figures Gand?.

. Probably, one of theniost annoying'troubles of the ordinary internalcombustion engine, is a leakyk piston or pistons. Due to the generalconstruction, these kvpistons are very hardandfdisagreeable tojget at.The'crank case with all lits bolts has to oe removed,"the

connecting rod disconnected, y,andthe piston pulled -down through the,vcylinder, or up through the head; then when the. trouble isr remedied;all these parts'and bolts have to bev i replaced, new g allboltstightened upwell. n I

All this timethe" mechanic 'doing'the work is in a verydisagreeableand-awkwardposi# y tio1'1,',whether the machine onlskids, orover` apit,"or he lyingon his back on the ground.

` vIt will bel readily seen byfglancing'at the drawings that all this.disagreeable work is gaskets probably installed `done away` with.ihezei'ankcase would only have tov be disturbedy in overhauling thecrank pin and lmain bearings,` whichis rare, as these parts practically'run in oil, and'have little wear, and then again lthe'tlirust in thisltype of engine is always down, with the 'exception of the" suctionstroke, and ythat/due to the weight'of they piston `androd ispracticallyy p nil The savingA intime` and expense in "removing pistonsshould be readily discerned. In the 'designing offintern'al; combustionengines, the designor Y"generallyilays out'the compression space to suitaselose as possible all localities', butit frequently lhappensl that amotor that gives excellent resultsatpa low .altitude will not act thesaine in' highaltitildes@l This .is due to rthedil'er/e'nee inatmospheric pressure as the air will not' flow in as' fast gasfin thelower altitudes. By '90 screwing theouter shell up or downj as in thevembodim".ent of Figures 1 to 5, or by using a distance piece as' inFig. 6`the proper density ,My vimprovemeini l`s "what might be ytermed aApiston'within afpiston, in tha fthe Fig. 8 isa devlce to keep boltsfrom lturnc spider'that lits int-othe'outer shell and is securedtherein. rI he "termj spider alluded to,l isv to be'understoodf'as almethod of lightlioo ToveXaInine rings.

ening up the structure to the eXtent that the inner shell need not litthe outer shell but here and there, but still have suicient bearingsurface for strength and rigidity.

Referring again to the drawings.

No. 1 is a cylinder showing piston mounted for reciprocation. It will beobserved that the outer. shell No. 2 is drawn line to line where itmeets inner shell No 3 on top, showing that the piston is set for amaximum compression space. :Bolts No. 4 are'shown tightened up. It maybe well to state here that the dili'erent figures are all drawn halt'size or" an engine ot this type, scale being 1/2 to 1". Actual sizesV ofcylinder being 3% bore and 4 stroke,V connecting rod 7 center to center.It will be noticed that the piston rings in shell No. 2 are l/S lowerthan inFig. which would amount to 1/4 full size,. and which isconsidered ample and which would allow plenty ot bolt hold when head, israised up to lessen the compression space and still. leave piston ringsbelow top of cylinder.

Both outer shell No. 2 andA inner shell No. 3: are turned" to a goodsliding fit at No. 5. Shell No. 2 has an internal thread cut into it atNo. 6 and. inner shell No. 3 an external thread at 6 with thisthreadlongerand lower in the shell topermit it being raised and' allnecessary threads be in service.

Take out bolts No. e, screw outer shell outot threads and pull out.

To alter compression. Take out bolts No. 4r, unscrew outer shell to thedesiredposition andy replace bolts No. 4. Piston should be on. uppercenter when this is done.A Two stray bolts entered in boltl holes ofouter shell and a bar between them for a lever enables this to be donevery easily.

Where pistons are supplied with the shells threaded at No. 6, two boltspreferably the two parallel with the wrist pin, are sufficient.Thisalso.v applies to pistons where the connecting rods has a bolted. oncap. on the wrist pin end. In this case the two bossesthatfare in way.ot the swinging of the captare also lett out.

DepressionsNo. 8V are preferably hexagon shaped and it isessential thatthebolt heads therein be prevented from turning, and crystalizing tromheatV as muchy as possible. A- nonburnable cement placed between thebolt head sides andthe heXagon shaped depressions, should. accomplishthis purpose. I have designed metal` protection and holding members 11.and 12fwhich are respectively A disclosed in developed form in FigureshSand 95 either of saidmembers being arranged to be engaged about/a4 bolthead after the latter is in a depression` 8.

The embodiment shown in Figures 6 and 7 can also-be made with orwithoutthe variable compression features. Drawing (No. ,6) shows thenonvariable in. that the "upper piston rings are closer to the top.y Tobe variable, the upper rings should be lower as in Fig. 1 and what isgenerally spoken ot'as a Vdistance piece inserted between the bosses onshell No. 3 and where they meet shell No. 2. As here shown, the distancepiece, or spacing member, 13 is in the form ot an an-V nular ringperforatedv to loosely receive the bolts 4. There being no threads onthis type, shell No. 3 is turned all the way, eX-v cepting betweenwhere-it may be spidered, to a nice sliding lit. As a precaution againstaccidents, all'tour bolts are used in this design. Y

Dotted circles No. 9 may not be used at all. Theyrepresentthe positionAwhere rivets may be ifit is desirous of usingfan. old stylepistonshell. rlhese shells are generally very thin, .therefore theyVwouldhave to be reint'orced by riveting a piece onto themtormed v forthat purpose.

vIvclaim--l In a piston for. a reciprocating'engine, an exterior memberdefining the piston. walls and piston head, anv interior member arranged'for threaded engagement with and vwithin saidv exterior member whereby'rel-V ative axial adjustment of said members in a plurality oiVpredetermined relative positions may be effected upon relative rotationot the members through rotative angles of less than 360 degrees, a wristpin mounted in said interior memberand a bolt operable from; the headend of said piston and arrang'c-idv to axially draw `said memberstogether to thereby lock them againstaxial and rotative displacement.

JOHN c. LEAs-Y.

